【作者】 高亚军；

【导师】 常庆瑞；

【作者基本信息】 西北农林科技大学 ， 土壤学， 2003， 硕士

【摘要】 陕北农牧交错带是我国土地退化最严重、生态环境最恶劣的地区之一，土壤风蚀和水蚀并存，随着西部大开发和陕北能源重化工基地的建设，土地荒漠化已经成为制约该地区经济持续增长和国民经济的可持续发展的重要因素之一。本研究以陕北农牧交错带土地荒漠化问题为研究对象，应用景观生态学理论、土地资源学和土壤发生学的基本原理，基于室内分析和野外考察资料，对不同类型和程度荒漠化土地的土壤理化性质和生物性质进行系统分析，探讨了荒漠化土壤质量评价指标体系的建立，对荒漠化土壤进行归类、评价，得出了土壤质量衰退模型，取得的主要成果和重要进展如下： 1．不同程度和类型荒漠化土壤理化性质和化学成分存在明显差异。0.25mm的粗砂粒：裸地＞草地＞灌木林地＞乔木林地，0.05-0.02mm的细砂粒的和＜0.002mm粘粒：乔木林地＞草地≈灌木林地＞裸地；固定沙丘、半固定沙丘和流动沙丘有机质平均含量为19.40g.kg^-1、9.36g.kg^-1和0.21g.kg^-1；土壤氮素和磷从流动沙丘到固定沙丘含量有所上升，钾素则变化不大，大部分剖面和层次土壤pH呈微碱性；土壤CaCO₃含量固定沙丘＞半固定沙丘＞流动沙丘；土壤阳离子交换量表现为乔木林地＞灌木林地和草地＞无植被裸地；乔木林地、灌木林地和草地＞5mm的团聚体平均达到了340g.kg^-1以上；流动沙丘的表层土壤，不存在2mm以上的团聚体，2-0.25mm的团聚体测定值很有可能是砂粒所致，而不是真正意义的团聚体。 2．不同生境荒漠化土壤酶活性的分布和特点与植被类型、土壤质地有密切关系，过氧化氢酶和蔗糖酶活性表现为：乔木＞草地＞灌木＞无植被土壤，碱性磷酸酶活性表现为：灌木＞乔木＞草地＞无植被土壤，脲酶活性：乔木林＞灌木林地＞草地＞无植被土壤。土壤酶活性总体上与土壤养分有着显著的相关关系，与土壤质地表现为砂壤土＞砂土。 3．不同荒漠化阶段植被类型的土壤微生物状况和土壤基本性质之间的关系密切。结果表明，细菌：灌木林地＞乔木林地＞草地＞无植被土壤，真菌和放线菌：乔木林地＞灌木林地＞草地＞无植被土壤，土壤微生物与土壤理化性质之间关系密切；砂粒与细菌、真菌、放线菌呈显著甚至极显著的负相关关系，粉粒和粘粒与细菌、真菌、放线菌呈显著或极显著正相关。 4．在分析已有资料数据和研究成果基础上，提出农牧交错带土地荒漠化评价的指标体系与方法，土壤质量指数的变化趋势能够表征土地荒漠化的类型和程度以及土壤质量的演化规律，从地表无植被的流动沙丘到生长乔木林的固定沙地土壤质量指数逐渐升高。化程度、应用主成分分析方法对荒漠化土壤进行类型划分，结果符合土地荒漠类型和土壤形成发育状况。更多还原

【Abstract】 It is one of furthest graveness of land degradation and of scurviness zone of environment between agriculture and husbandry interlace zone in north of shannxi province. Soil water-erosion and wind-erosion is coexistent, land desertification is one of important restrict factor between economy persistence increase and durative development of national economy in this zone, along with great exploitation in west and construction of energy chemical industry base. Based on soil desertification between agriculture and husbandry interlace zone in north of shannxi province, on the basis of theories of landscape ecology, land resource and principle of soil genesic science, through indoor analyzing and field surveying data , the properties of soil physical and chemical characteristics and of biology are systemic analyzed about desertification soil of different type and degree, establish of soil quality index system in desertification is discussed, appraised soil quality, degraded model of soil quality is attained through soil classify and evaluate in desertification zone, achieving primary achievements and important evolves are as follows: I. Desertification soil Soil physical and chemical characteristics have great differenceThe coarse sand >0.25mm: unvegetation soil > meadow > shrubby woodland>arboreal woodland, the fine sand 0.05-0.02mm and clay: arboreal woodland > meadow = shrubby woodland>unvegetation soil; fixed dune, half fixed dune and flowing dune have average OM content are 19.40g.kg-1, 9.36g.kg-1 and 0.21g.kg-1; N and P are raised from flowing dune to fixed dune, and K is not change great, the PH in mostly profile and arrangement is slight alkalinity ; the content of CaCO3 is fixed dune> half fixed dune; the CEC is arboreal woodland>shrubby woodland and meadow >unvegetation soil; arboreal woodland , the cluster >5mm in shrubby woodland and meadow average reach 340g.kg-1; the topsoil in flowing dune has not cluster >2mm, and the cluster in 2-0.25mm which had been mensurated is likely to be sand, not the cluster in deed.II. The distributing and charact of Soil-enzyme activity in different habitation of desertification zone have great relation with vegetation type and soil texture, catalase and cane sugar enzyme activity are: arboreal woodland> meadow> shrubby woodland> unvegetation soil, alkalescent Phosphats activity is: shrubby woodland>arboreal woodland> meadow> unvegetation soil, urease activity is: arboreal woodland> shrubby woodland>meadow> unvegetation soil. The Soil-enzyme activity have best remarkable relationship with soil fertility in a whole and it is sand loam soil>sand soil.III. Status of microbe and soil basal property in different vegetation types and in different desertification phaseThe result are showed that bacteria: shrubby woodland>arboreal woodland> meadow>unvegetation soil, actinomyce and epiphyte : arboreal woodland > shrubby woodland > meadow>unvegetation soil, soil microbe and soil physical and chemical characteristics are consanguineous; they have remarkable and best remarkable minus relationship in sand with bacteria , actinomyce and epiphyte, slit and clay with bacteria, actinomyce and epiphyte have remarkable and best remarkable correctitude relationship.IV. Based on known data and production of research, putting forward index system and method of land desertification evaluate in agriculture and animal husbandry interlace zone, variational trend of soil quality index can indicate the type and degreee of land desertification and the evolutive law of soil quality, soil qulity index is gradually enhanced from flowing dune in without vegetation to fixed dene in growing arbor woodland.V. Type divisions are processed to desertification soil through employ the analytical methods of primary component. Its show that the results accord the degree , type and status of soil form and growth about desertification land.更多还原